Fungicidal mixtures

ABSTRACT

Advantageous combinations of an oxazolidinone and cymoxanil (or their agriculturally suitable salts) and their use to control fungus disease in plants are disclosed, the oxazolidinone having the formula ##STR1##

This application represents the national filing under 35 USC 371 ofInternational Application No. PCT/US96/11346 filed Jul. 3, 1996 andclaims priority, in part, of U.S. Application Ser. No. 60/001,088 filedJul. 12, 1995.

BACKGROUND OF THE INVENTION

This invention pertains to agriculturally suitable compositionscontaining an advantageous combination of certain fungicidaloxazolidinone compounds with another fungicide, and methods for the useof such compositions to control fungus disease in certain plants.

Fungicides that effectively control plant diseases are in constantdemand by growers. Plant diseases are highly destructive, difficult tocontrol and quickly develop resistance to commercial fungicides.Combinations of pesticides are often used to facilitate disease control,to broaden spectrum of control and to retard resistance development. Itis recognized in the art that the advantages of particular pesticidecombinations can often vary, depending on such factors as the particularplant and plant disease to be treated, and the treatment conditions.

WO 90/12791 discloses certain oxazolidinone compounds as fungicidesincluding 5-methyl-5-(4-phenoxyphenyl)-3-phenylamino-2,4-oxazolidinone(i.e., the Formula I compound defined herein). U.S. Pat. No. 3,954,992discloses cymoxanil as a fungicide. Synergistic combinations ofcymoxanil and oxazolidenylacetamides such as oxadixyl are disclosed inU.S. Pat. No. 4,507,310. These references neither disclose nor suggestsynergistic compositions comprising an oxazolidinone and cymoxanil.

SUMMARY OF THE INVENTION

This invention pertains to an advantageous combination of cymoxanil(and/or an agriculturally suitable salt thereof) and the oxazolidinoneof Formula I. This invention provides fungicidally active compositionscomprising a fungicidally effective amount of a mixture of (a) at leastone compound selected from the oxazolidinone of Formula I andagriculturally suitable salts thereof, and (b) at least one compoundselected from cymoxanil and agriculturally suitable salts thereof, andoptionally (c) at least one of a surfactant, a solid diluent or a liquiddiluent wherein the weight ratio of component (a) to component (b) isfrom about 17:1 to about 1:100. ##STR2##

The compound of Formula I is also known as5-methyl-5-(4-phenoxyphenyl)-3-phenylamino-2,4-oxazolidinone.

This invention also provides methods for controlling plant diseasescaused by fungal plant pathogens comprising applying to the plant orportion thereof to be protected, or to the plant seed or seedling to beprotected one of the following:

1) an effective amount of a fungicidal composition comprising (a) thecompound of Formula I as defined above, or an agriculturally suitablesalt thereof, (b) cymoxanil, or an agriculturally suitable salt thereof,and (c) at least one of a surfactant, a solid diluent or a liquiddiluent;

2) (i) an effective amount of a first composition comprising (a) thecompound of Formula I as defined above, or an agriculturally suitablesalt thereof, and (c1) at least one of a surfactant, solid or liquiddiluent; and (ii) an effective amount of a second composition comprising(b) cymoxanil, or an agriculturally suitable salt thereof, and (c2) atleast one of a surfactant, a solid diluent or a liquid diluent, saidfirst and second compositions applied sequentially in any order; or

3) an effective amount of a physical mixture of the first and secondcompositions as defined in 2 above.

The weight ratio of the compound of (a) to the compound of (b) appliedis normally from about 17:1 to 1:100, and the compound of (a) and thecompound of (b) are normally applied in amounts effective to providecontrol of the fungal disease which is greater than the additive controlof that fungal disease provided by the compound of (a) and the compoundof (b) individually.

DETAILED DESCRIPTION OF THE INVENTION

It has been found that combinations of the compound of Formula I andcymoxanil provide control of certain plant diseases which issubstantially and surprisingly enhanced over the expected simplyadditive control by said components.

Cymoxanil, tradename Curzate®, is a commercially available foliarfungicide for control of late blight and downy mildew diseases,particularly for systemic and curative control of potato late blight andgrape downy mildew, having the formula: ##STR3## which is also known as2-cyano-N- (ethylamino)carbonyl!-2-(methoxyimino)acetamide.

The compound of Formula I can exist as enantiomers. One skilled in theart will appreciate that one enantiomer may be more active and/or mayexhibit beneficial effects when enriched relative to the otherenantiomer or when separated from the other enantiomer. Additionally,the skilled artisan knows how to separate, enrich, and/or to selectivelyprepare said enantiomers. Accordingly, the present invention comprisescompositions of the individual enantiomers or optically active mixturesof the oxazolidinone of Formula I as well as agriculturally suitablesalts thereof in admixture with cymoxanil or an agriculturally suitablesalt thereof. ##STR4##

Cymoxanil can be prepared by the procedures described in U.S. Pat. No.3,954,992. Preparation of the compositions of the present inventioncontaining cymoxanil and the compound of Formula I is discussed later inthe application.

The compound of Formula I can be prepared as depicted in Scheme 1 anddescribed in WO 94/11359. ##STR5## wherein: R⁶ is C₁ -C₄ alkyl; and

Y is 1-imidazolyl or 1,2,4-triazolyl.

Reaction conditions suitable for preparing the compound of Formula I areas follows. For the conversion of esters of Formula II to compounds ofFormula IV, the suitable solvents include inert organic solvents.Preferred solvents are methylene chloride, chloroform, carbontetrachloride, hexanes, tetrahydrofuran, tert-butyl methyl ether,dioxanes, chlorobenzene, o-dichlorobenzene (ODCB), toluene, xylenes, andsuitable combinations thereof. The most preferred solvents are selectedfrom the group consisting of chlorobenzene, ODCB, toluene, and xylenes.The reaction temperatures can range from about 10° C. to about 75° C.Preferred temperatures are from about 40° C. to about 60° C. Suitablereaction pressures are from about 1.0×10⁵ to about 5.1×10⁵ Pascals. Thepreferred pressure is 1×10⁵ Pascals. The reaction times are typically 1to 24 hours, preferably 3 to 6 hours. A suitable ratio of Formula III toII is from about 1:1 to 2:1. The preferred ratio is from about 1.1:1 to1.8:1. Suitable bases for this reaction include trialkylamines,imidazole, pyridine, picolines or other substituted pyridinederivatives.

For the conversion of compounds of Formula IV to the2,4-oxazolidinedione of Formula I, suitable solvents are as noted abovefor the condensation of Formulae II and III. The preferred solvents arethose disclosed above as preferred. The reaction temperatures are fromabout 0° C. to about 75° C. Preferred temperatures are from about 10° C.to about 50° C. Reaction pressures are from about 1.0×10⁵ to about5.1×10⁵ Pascals. The preferred pressure is 1×10⁵ Pascals. The reactiontimes are typically 1 to 24 hours, preferably 2 to 6 hours. The acidssuitable for catalyzing the reaction are selected from the groupconsisting of alkyl and aryl carboxylic acids, trialkylammonium halidesand combinations thereof. The preferred acids are acetic acid andtriethylammonium chloride. The most preferred acid is triethylammoniumchloride. Suitable ratios of phenylhydrazine to Formula IV is from about2:1 to 1:1. The preferred ratio is from about 1.6:1 to 1.1:1.

The carbonylating agent of Formula III may be added as a pure compound,a solution of the pure compound in an inert solvent, or prepared in situin the presence of the ester of Formula II. The preferred processinvolves preparation of the carbonylating agent in situ.

Methods for preparing compounds of Formula III, including in situmethods, from phosgene or phosgene equivalents such as diphosgene(trichloromethyl chloroformate) or triphosgenebis(trichloromethyl)carbonate)! and either imidazole or triazole areknown in the art (see Org. Syntheses. Coll. Vol. 5, 201, (1973)).Reactions wherein HCl is liberated require a base to trap the acid. Asuitable base is a trialkylamine or imidazole, or combinations thereof.The preferred base is triethylamine. 1,1'-Carbonylditriazole (FormulaIII wherein Y=1,2,4-triazolyl) can also be prepared by treating a metalalkali salt of triazole, preferably the potassium salt, with phosgene(or phosgene equivalent) in a solvent. Phase transfer catalysts arepreferably added to reactions wherein the triazole salt has lowsolubility in the solvent. For example, phase transfer catalysts arepreferred when xylenes or toluene is used. Any phase transfer catalystknown to one skilled in the art is suitable. Tetraalkylammonium halidesare preferred. The triazole salt is prepared by treating triazole with asuitable base, such as sodium hydroxide or sodium ethoxide. Thepreferred relative amount of alkali metal base to triazole to phosgeneis 0.5:1.0:0.6.

Base is also necessary to catalyze the condensation of Formulae II andIII. As previously stated, suitable base catalysts are trialkylamines,imidazole, pyridine, picolines or other substituted pyridines. When1,1'-carbonyldiimidazole is used (Formula III wherein Y=1-imidazolyl),the imidazole which is liberated upon reaction with Formula II serves asthe catalyst. When 1,1'-carbonylditriazole is used, the preferred baseis pyridine, a picoline, or a mixture of picoline isomers.

Compounds of Formula IV may be isolated and purified, or treated in situwith phenylhydrazine and acid to form the 2,4-oxazolidinedione ofFormula I. The preferred method involves treatment of Formula IV in situwith phenylhydrazine. After the formation of the carbamate of Formula IVis complete, excess carbonylating agent can be decomposed by theaddition of water.

The 2-hydroxycarboxylic acid esters of Formula II can be prepared by anumber of methods known in the literature:

(1) They can be formed from the corresponding 2-hydroxycarboxylic acidsby esterification as is well known in the literature. The2-hydroxycarboxylic acids can be prepared from methyl ketones byformation of cyanohydrins, then hydrolysis, as is also known. Forexample, Org. Syntheses. Coll. Vol. 4, 58 (1968) teaches the preparationof atrolactic acid from acetophenone.

(2) The esters can also be synthesized from ketone cyanohydrins bytreatment with alcohols in the presence of HCl to afford the iminoetherhydrochlorides, followed by hydrolysis.

(3) A third method known for preparing 2-hydroxycarboxylic acids andesters involves treating 2-keto-acids or 2-keto-esters withnucleophilic-organometallic reagents such as Grignard reagents, andalkyl- and aryl-lithium reagents. For example, R. G. Salomon et al.teaches the preparation of some esters of Formula II by the addition ofaryl-Grignard reagents to pyruvate esters (J. Org. Chem. (1982), 47,4692). Similarly, some 2-hydroxycarboxylic acids may be prepared by theregioselective nucleophilic addition of an aryl organometallic reagentto the metal salt (e.g., sodium salt) of pyruvic acid.

(4) Another method described in the literature for preparing some2-aryl-2-hydroxyesters and acids is by acylation of aromatic rings withactivated carbonyl compounds in the presence of a protic or Lewis acid.Aromatic substrates capable of undergoing reactions of this type arebenzene, diphenyl ether, and other aromatic compounds known to be ofsufficient reactivity to undergo Friedel-Crafts-type reactions. In thecase of mono-substituted benzene derivatives, the acylation occurspreferentially, but not necessarily exclusively, para to the point ofattachment of the substituent. For example, see Org. Syntheses, Coll.Vol. 3, 326, (1955), Salomon et al., J. Org. Chem., (1982), 47, 4692,and U.S. Pat. No. 4,922,010.

Carbonyl compounds known to undergo this reaction include pyruvateesters and acids, glyoxylate esters and acids, and diesters ofoxomalonates. The acids used in the acylation reaction can either beprotic in nature, for example, a mixture of acetic and sulfuric acid, ora Lewis acid such as aluminum chloride, tin tetrachloride, titaniumtetrachloride, or other Lewis acid known to effect Friedel-Crafts-typereactions. The acid can be used either catalytically or in excess. Insome cases, the acid may react destructively with the carbonyl substrateand excess carbonyl compound must be used.

Fungicides that effectively control plant fungi, particularly of theclass Oomycetes, such as Phytophthora spp. and Plasmopara spp., are inconstant demand by growers. Combinations of fungicides are often used tofacilitate disease control and to retard resistance development.Mixtures of fungicides may provide significantly better disease controlthan could be predicted based on the activity of the individualcomponents. This synergism has been described as "the cooperative actionof two components of a mixture, such that the total effect is greater ormore prolonged than the sum of the effects of the two (or more) takenindependently" (see Tames, P. M. L., Neth. J. Plant Pathology, (1964),70, 73-80). It has been found that compositions containing the compoundof Formula I and cymoxanil exhibit synergistic effects.

The presence of a synergistic effect between two active ingredients isestablished with the aid of the Colby equation (see Colby, S. R. InCalculating Synergistic and Antagonistic Responses of HerbicideCombinations, Weeds, (1967), 15, 20-22): ##EQU1##

Using the methods of the Colby, the presence of a synergisticinteraction between two active ingredients is established by firstcalculating the predicted activity, p, of the mixture based onactivities of the two components applied alone. If p is lower than theexperimentally established effect, synergism has occurred. In theequation above, A is the fungicidal activity in percentage control ofone component applied alone at rate x. The B term is the fungicidalactivity in percentage control of the second component applied at ratey. The equation estimates p, the fungicidal activity of the mixture of Aat rate x with B at rate y if their effects are strictly additive and nointeraction has occurred.

In this invention, fungicidal activities provided by compositions ofFormula I and cymoxanil alone are compared with that of a composition ofa compound of Formula I and cymoxanil. Based on the description ofsynergism developed by Colby, compositions of the present invention areconsidered to be synergistically useful. More particularly, thecompositions comprising (a) at least one compound selected from5-methyl-5-(4-phenoxyphenyl)-3-phenylamino-2,4-oxazolidinone and itsagriculturally suitable salts, (b) at least one compound selected from2-cyano-N- (ethylamino)carbonyl!-2-(methoxyimino)acetamide and itsagriculturally suitable salts, and (c) at least one of a surfactant, asolid diluent or a liquid diluent wherein the weight ratio of component(a) and component (b) is between about 17:1 and about 1:100, can besynergistic. Moreover, compositions comprising components (a) and (b)alone can be conveniently mixed with an optional diluent prior toapplying to the crop to be protected. The weight ratio of component (a)to component (b) is preferably from about 8:1 to about 1:25; and is morepreferably from about 4:1 to about 1:10. Of note are compositionswherein the weight ratio of component (a) to component (b) is from about3:2 to about 1:3. Accordingly, this invention provides an improvedmethod of combating fungi, particularly fungi of the class Oomycetessuch as Phytophthora spp. and Plasmopara spp., in crops, especiallypotatoes, grapes and tomatoes.

The compound of Formula I and cymoxanil can be formulated in two ways:

1. the compound of Formula I and cymoxanil can be formulated separatelyand applied separately or applied simultaneously in an appropriateweight ratio, e.g. as a tank mix; or

2. the compound of Formula I and cymoxanil can be formulated together inthe weight ratios as defined herein.

The fungicidal composition of the present invention comprises aneffective amount of a mixture of the compound of Formula I and cymoxanilas defined above as the active ingredients and at least one of asurfactant, a solid diluent or a liquid diluent. The composition of thisinvention is typically used in formulation with an agriculturallysuitable carrier comprising a liquid or solid diluent and/or asurfactant wherein the formulation is consistent with the physicalproperties of the active ingredients, mode of application andenvironmental factors such as soil type, moisture and temperature.Useful formulations include liquids such as solutions (includingemulsifiable concentrates), suspensions, emulsions (includingmicroemulsions and/or suspoemulsions) and the like which optionally canbe thickened into gels. Useful formulations further include solids suchas dusts, powders, granules, pellets, tablets, films, and the like whichcan be water-dispersible ("wettable") or water-soluble. Activeingredients can be (micro)encapsulated and further formed into asuspension or solid formulation; alternatively the entire formulation ofactive ingredients can be encapsulated (or "overcoated"). Encapsulationcan control or delay release of the active ingredients. Sprayableformulations can be extended in suitable media and used at spray volumesfrom about one to several hundred liters per hectare. High-strengthcompositions are primarily used as intermediates for furtherformulation.

The formulations will typically contain effective amounts of activeingredients, diluent and surfactant within the following approximateranges which add up to 100 percent by weight.

    ______________________________________                                                      Weight Percent                                                                Active                                                                        Ingredients                                                                           Diluent   Surfactant                                    ______________________________________                                        Water-Dispersible and Water-                                                                  5-90      0-94      1-15                                      soluble Granules, Tablets                                                     and Powders.                                                                  Suspensions, Emulsions,                                                                       5-50      40-95     0-15                                      Solutions (including                                                          Emulsifiable Concentrates)                                                    Dusts           1-25      70-99     0-5                                       Granules and Pellets                                                                          0.01-99     5-99.99 0-15                                      High Strength Compositions                                                                    90-99     0-10      0-2                                       ______________________________________                                    

Typical solid diluents are described in Watkins, et al., Handbook ofInsecticide Dust Diluents and Carriers, 2nd Ed., Dorland Books,Caldwell, N.J. Typical liquid diluents are described in Marsden,Solvents Guide, 2nd Ed., Interscience, New York, 1950. McCutcheon'sDetergents and Emulsifiers Annual, Allured Publ. Corp., Ridgewood, N.J.,as well as Sisely and Wood, Encyclopedia of Surface Active Agents,Chemical Publ. Co., Inc., New York, 1964, list surfactants andrecommended uses. All formulations can contain minor amounts ofadditives to reduce foam, caking, corrosion, microbiological growth andthe like, or thickeners to increase viscosity.

Surfactants include, for example, polyethoxylated alcohols,polyethoxylated alkylphenols, polyethoxylated sorbitan fatty acidesters, dialkyl sulfosuccinates, alkyl sulfates, alkylbenzenesulfonates, organosilicones, N,N-dialkyltaurates, lignin sulfonates,naphthalene sulfonate formaldehyde condensates, polycarboxylates, andpolyoxyethylene/polyoxypropylene block copolymers. Solid diluentsinclude, for example, clays such as bentonite, montmorillonite,attapulgite and kaolin, starch, sugar, silica, talc, diatomaceous earth,urea, calcium carbonate, sodium carbonate and bicarbonate, and sodiumsulfate. Liquid diluents include, for example, water,N,N-dimethylformamide, dimethyl sulfoxide, N-alkylpyrrolidone, ethyleneglycol, polypropylene glycol, paraffins, alkylbenzenes,alkylnaphthalenes, oils of olive, castor, linseed, tung, sesame, corn,peanut, cotton-seed, soybean, rape-seed and coconut, fatty acid esters,ketones such as cyclohexanone, 2-heptanone, isophorone and4-hydroxy-4-methyl-2-pentanone, and alcohols such as methanol,cyclohexanol, decanol and tetrahydrofurfuryl alcohol.

Solutions, including emulsifiable concentrates, can be prepared bysimply mixing the ingredients. Dusts and powders can be prepared byblending and, usually, grinding as in a hammer mill or fluid-energymill. Suspensions are usually prepared by wet-milling; see, for example,U.S. Pat. No. 3,060,084. Granules and pellets can be prepared byspraying the active materials upon preformed granular carriers or byagglomeration techniques. See Browning, "Agglomeration", ChemicalEngineering, Dec. 4, 1967, pp 147-48, Perry's Chemical Engineer'sHandbook, 4th Ed., McGraw-Hill, New York, 1963, pages 8-57 andfollowing, and WO 91/13546. Pellets can be prepared as described in U.S.Pat. No. 4,172,714. Water-dispersible and water-soluble granules can beprepared as taught in U.S. Pat. No. 4,144,050, U.S. Pat. No. 3,920,442and U.S. Pat. No. DE 3,246,493. Tablets can be prepared as taught inU.S. Pat. No. 5,180,587, U.S. Pat. No. 5,232,701 and U.S. Pat. No.5,208,030. Films can be prepared as taught in GB 2,095,558 and U.S. Pat.No. 3,299,566.

For further information regarding the art of formulation, see U.S. Pat.No. 3,235,361, Col. 6, line 16 through Col. 7, line 19 and Examples10-41; U.S. Pat. No. 3,309,192, Col. 5, line 43 through Col. 7, line 62and Examples 8, 12, 15, 39, 41, 52, 53, 58, 132, 138-140, 162-164, 166,167 and 169-182; U.S. Pat. No. 2,891,855, Col. 3, line 66 through Col.5, line 17 and Examples 1-4; Klingman, Weed Control as a Science, JohnWiley and Sons, Inc., New York, 1961, pp 81-96; and Hance et al., WeedControl Handbook, 8th Ed., Blackwell Scientific Publications, Oxford,1989.

In the following Examples, all percentages are by weight and allformulations are worked up in conventional ways.

EXAMPLE A

Wettable Powder

    ______________________________________                                        5-methyl-5-(4-phenoxyphenyl)-                                                                        27.9%                                                  3-phenylamino-2,4-oxazolidinone                                               cymoxanil              37.1%                                                  dodecylphenol polyethylene glycol ether                                                              2.0%                                                   sodium ligninsulfonate 4.0%                                                   sodium silicoaluminate 6.0%                                                   montmorillonite (calcined)                                                                           23.0%.                                                 ______________________________________                                    

EXAMPLE B

Granule

    ______________________________________                                        5-methyl-5-(4-phenoxyphenyl)-                                                                        5.0%                                                   3-phenylamino-2,4-oxazolidinone                                               cymoxanil              5.0%                                                   attapulgite granules (low volatile matter,                                                           90.0%.                                                 0.71/0.30 mm; U.S.S. No. 25-50 sieves)                                        ______________________________________                                    

EXAMPLE C

Extruded Pellet

    ______________________________________                                        5-methyl-5-(4-phenoxyphenyl)-                                                                      10.7%                                                    3-phenylamino-2,4-oxazolidinone                                               cymoxanil            14.3%                                                    anhydrous sodium sulfate                                                                           10.0%                                                    crude calcium ligninsulfonate                                                                      5.0%                                                     sodium alkylnaphthalenesulfonate                                                                   1.0%                                                     calcium/magnesium bentonite                                                                        59.0%.                                                   ______________________________________                                    

EXAMPLE D

Emulsifiable Concentrate

    ______________________________________                                        5-methyl-5-(4-phenoxyphenyl)-                                                                      10.0%                                                    3-phenylamino-2,4-oxazolidinone                                               cymoxanil            10.0%                                                    blend of oil soluble sulfonates                                                                    10.0%                                                    and polyoxyethylene ethers                                                    isophorone           70.0%.                                                   ______________________________________                                    

The compositions of this invention are useful as plant disease controlagents. The present invention further comprises a method for controllingplant diseases caused by fungal plant pathogens comprising applying tothe plant or portion thereof to be protected, or to the plant seed orseedling to be protected, an effective amount of a fungicidalcomposition of the compound of Formula I and cymoxanil. Alternatively,fungicidal compositions containing only one of a composition of thecompound of Formula I or cymoxanil can be applied followed byapplication of the other composition. Further, separate compositions ofthe compound of Formula I and a composition of cymoxanil can be combinedas a physical mixture prior to application, e.g., a tank mix, andapplied simultaneously. In any event, the compound of Formula I andcymoxanil are desirably applied in amounts effective to provide controlof a fungal disease which is greater than the additive control of thatfungal disease provided by the compound of Formula I and cymoxanilindividually. The compositions of this invention provide control ofdiseases caused by a broad spectrum of fungal plant pathogens in theBasidiomycete, Ascomycete, Deuteromycete classes and, in particular, theOomycete class. They are effective in controlling a broad spectrum ofplant diseases, particularly foliar pathogens of ornamental, vegetable,field, cereal, and fruit crops, particularly pathogens in potato, tomatoand grapevines. These pathogens include Plasmopara viticola,Phytophthora infestans, Peronospora tabacina, Pseudoperonosporacubensis, Pythium aphanidermatum, Alternaria brassicae, Septorianodorum, Septoria tritici, Cercosporidium personatum, Cercosporaarachidicola, Pseudocercosporella herpotrichoides, Cercospora beticola,Botrytis cinerea, Monilinia fructicola, Pyricularia oryzae, Podosphaeraleucotricha, Venturia inaequalis, Erysiphe graminis, Uncinula necatur,Puccinia recondita, Puccinia graminis, Hemileia vastatrix, Pucciniastriiformis, Puccinia arachidis, Rhizoctonia solani, Sphaerothecafuliginea, Fusarium oxysporum, Verticillium dahliae, Pythiumaphanidermatum, Phytophthora megasperma, Scierotinia sclerotiorum,Sclerotium rolfsii, Erysiphe polygoni, Pyrenophora teres, Gaeumannomycesgraminis, Rynchosporium secalis, Fusarium roseum, Bremia lactucae andother generea and species closely related to these pathogens. Of note istheir use to control Phytophthora infestans which is a pathogen involvedin various fungal diseases (for example, potato late blight and tomatolate blight). Also of note is their use to control Plasmopara viticolawhich is a pathogen involved in such fungal diseases as grape downymildew.

The compositions of this invention can also be mixed with one or moreother insecticides, fungicides, nematocides, bactericides, acaricides,semiochemicals, repellents, attractants, pheromones, feeding stimulantsor other biologically active compounds to form a multi-componentpesticide giving an even broader spectrum of agricultural protection.Examples of such agricultural protectants with which compositions ofthis invention can be formulated are: insecticides such as abamectin,acephate, azinphos-methyl, bifenthrin, buprofezin, carbofuran,chlorpyrifos, chlorpyrifos-methyl, cyfluthrin, beta-cyfluthrin,deltamethrin, diafenthiuron, diazinon, diflubenzuron, dimethoate,esfenvalerate, fenpropathrin, fenvalerate, fipronil, flucythrinate,tau-fluvalinate, fonophos, imidacloprid, isofenphos, malathion,metaldehyde, methamidophos, methidathion, methomyl, methoprene,methoxychlor, monocrotophos, oxamyl, parathion, parathion-methyl,permethrin, phorate, phosalone, phosmet, phosphamidon, pirimicarb,profenofos, rotenone, sulprofos, tebufenozide, tefluthrin, terbufos,tetrachlorvinphos, thiodicarb, tralomethrin, trichlorfon andtriflumuron; fungicides such as azoxystrobin (ICIA5504), benomyl,blasticidin-S, Bordeaux mixture (tribasic copper sulfate),bromuconazole, captafol, captan, carbendazim, chloroneb, chlorothalonil,copper oxychloride, copper salts, cyproconazole, cyprodinil (CGA219417), diclomezine, dicloran, difenoconazole, dimethomorph,diniconazole, diniconazole-M, dodine, edifenphos, epoxyconazole (BAS480F), fenarimol, fenbuconazole, fenpiclonil, fenpropidin,fenpropimorph, fluquinconazole, flusilazole, flutolanil, flutriafol,folpet, fosetyl-aluminum, furalaxyl, hexaconazole, ipconazole,iprobenfos, iprodione, isoprothiolane, kasugamycin, kresoxim-methyl (BAS490F), mancozeb, maneb, mepronil, metalaxyl, metconazole, myclobutanil,neo-asozin (ferric methanearsonate), oxadixyl, penconazole, pencycuron,probenazole, prochloraz, propiconazole, pyrifenox, pyroquilon, sulfur,tebuconazole, tetraconazole, thiabendazole, thiophanate-methyl, thiram,triadimefon, triadimenol, tricyclazole, triticonazole, uniconazole,validamycin and vinclozolin; nematocides such as aldoxycarb andfenamiphos; bactericides such as streptomycin; acaricides such asamitraz, chinomethionat, chlorobenzilate, cyhexatin, dicofol,dienochlor, fenazaquin, fenbutatin oxide, fenpropathrin, fenpyroximate,hexythiazox, propargite, pyridaben and tebufenpyrad; and biologicalagents such as Bacillus thuringiensis, Bacillus thuringiensis deltaendotoxin, baculovirus, and entomopathogenic bacteria, virus and fungi.

In certain instances, combinations with other fungicides having asimilar spectrum of control but a different mode of action will beparticularly advantageous for resistance management.

Preferred for better control of plant diseases caused by fungal plantpathogens (e.g., lower use rate or broader spectrum of plant pathogenscontrolled) or resistance management are mixtures of a the compositionsof this invention with a fungicide selected from the group azoxystrobin(ICIA5504), copper salts (including Bordeaux mixture and copperoxychloride), fosetyl-aluminum, kresoxim-methyl (BAS 490F), metalaxyl,oxadixyl and mancozeb with fosetyl-aluminum and copper salts being themost useful. Specifically preferred mixtures of the two fungicides ofthis invention (Compound I refers to the compound of Formula I) with anadditional fungicide are selected from the group: azoxystrobin(ICIA5504) and the mixture of cymoxanil and Compound I; copper salts andthe mixture of cymoxanil and Compound I; fosetyl-aluminum and themixture of cymoxanil and Compound I; kresoxim-methyl (BAS 490F) and themixture of cymoxanil and Compound I; metalaxyl and the mixture ofcymoxanil and Compound I; oxadixyl and the mixture of cymoxanil andCompound I; and mancozeb and the mixture of cymoxanil and Compound I.

Plant disease control is ordinarily accomplished by applying aneffective amount of a composition of this invention either pre- orpost-infection, to the portion of the plant to be protected such as theroots, stems, foliage, fruit, seeds, tubers or bulbs, or to the media(soil or sand) in which the plants to be protected are growing. Thecomposition can also be applied to the seed to protect the seed andseedling.

Rates of application for the compositions can be influenced by manyfactors of the environment and should be determined under actual useconditions. Foliage can normally be protected when treated at a rate offrom less than 1 g/ha to 5,000 g/ha of aggregate active ingredient.Aggregate active ingredient is defined as the total combined weight ofactive ingredients. Seed and seedlings can normally be protected whenseed is treated at a rate of from 0.1 to 10 g of aggregate activeingredient per kilogram of seed. Preferred foliar application of acomposition of this invention are compositions containing 1 to 400 g/haof the compound of Formula I and 4 to 240 g/ha of cymoxanil as activeingredients.

The following Examples demonstrate the compositions and methods of thepresent invention and provide experimental evidence for synergy betweenthe compound of Formula I and cymoxanil in controlling late blight ofpotatoes and tomatoes caused by Phytophthora infestans and downy mildewof grapes caused by Plasmopara viticola. The pathogen control protectionafforded by these compositions is not limited, however, to thesespecies. However, the synergy demonstrated in the following examples wasnot as consistently observed under all conditions (e.g., heavy rain orwashoff) or for all plant diseases.

EXAMPLE 1 Preparation of5-Methyl-5-(4-phenoxyphenyl)-3-phenylamino-2,4-oxazolidinedione(Compound I)

A mixture of 14.3 g of ethyl 2-(4-phenoxyphenyl)lactate (34 g of amixture containing 14.3 g of ethyl 2-(4-phenoxyphenyl)lactate and 19.7 gof diphenyl ether), 9.7 g of 1,1'-carbonyldiimidazole and 100 mL ofmethylene chloride was agitated at 25° C. for 19 h. Water (0.30 mL) wasadded and the mixture was agitated for 15 min. Then, 5 mL of acetic acidand 7.4 g of phenylhydrazine were added. After agitating at 25° C. for24 h, 100 mL of water was added. The pH was lowered to 2 withhydrochloric acid, and the aqueous layer was removed. After washing themethylene chloride layer with 50 mL of water, the solvent was evaporatedunder vacuum. The oily residue was mixed with 150 mL hexane and 15 mL ofethyl acetate, heated to 65° C., cooled to 20° C., and then filtered.The solids were washed with 100 mL of a mixture of 20 mL ethyl acetateand 80 mL of hexane and then dried. The title product (15.2 g) wasobtained with a m.p. of 137-139° C.

EXAMPLE 2 Synergistic Combination of5-methyl-5-(4-phenoxyphenyl)-3-phenylamino-2,4-oxazolidinedione(Compound I) and Cymoxanil

Test compositions are prepared as follows: To 182.5 mg of a 20%microemulsion containing Compound I (36.5 mg of active ingredient) isadded 32 mL of distilled water to form a stock solution of Compound I. A20% microemulsion of Compound I is prepared by mixing together 20% ofCompound I, 40% N-methylpyrrolidinone and 40% Microstep H303 (allpercentages by weight). Microstep H303 is an emulsifier blend availablefrom the Stepan Co., Northfield, Ill. 60093. Cymoxanil is used as thecommercially available 50% wettable powder (WP) formulation of Curzate®.A stock solution is made by adding 32 mL of distilled water to 73 mg ofthe wettable powder formulation (36.5 mg of active ingredient). Thestock solutions are then diluted with distilled water and applied byspraying. The following dilutions are prepared to effect the applicationrates:

    ______________________________________                                        Rate (g ai/ha).sup.(1)                                                                    Stock Solution (mL)                                                                        Distilled water (mL)                                 ______________________________________                                        8           0.5          59.5                                                 35          2            58                                                   70          4            56                                                   140         8            52                                                   280         16           44                                                   ______________________________________                                         .sup.(1) grams of active ingredient per hectare.                         

For applications of a single active ingredient, the total volume ofspray is equal to the volume of stock solution plus the volume ofdistilled water added to achieve the desired rate. For simultaneousapplication of Compound I and cymoxanil, the appropriately diluted stocksolutions containing Compound I or cymoxanil are combined and thenapplied by spraying.

Potatoes (Solanum tuberosum `Superior`) grown from tissue culture aretransplanted to 4-inch (10.16 cm) pots and maintained in the greenhouse.Five to six weeks after transplanting, uniform plants 6-8 inches(15.24-20.32 cm) tall are selected. The plants are sprayed withcymoxanil alone at rates of 8, 35 and 140 g ai/ha, or with Compound Ialone at rates of 8, 35 and 140 g ai/ha or with combinations ofcymoxanil and Compound I in all rate combinations. After spraying, theplants are maintained in a greenhouse for 6 days. Plants are theninoculated with an aerosol suspension of P. infestans zoospores (2×10⁴zoospores/mL) in deionized water. The plants are then immediately placedin a humidification chamber (>98% relative humidity) for 24 hours toprovide environmental conditions necessary for infection afterwards and,following a 24 hour transition period in a lighted growth chamber, theplants are returned to the greenhouse. Disease is evaluated 6 days afterinoculation by recording the percentage of leaf surface with typical P.infestans lesions on the basal four fully expanded true leaves. Eachtreatment is replicated 3 times for each test. The mean percentagedisease control is summarized in Table 1. Tests where the control levelis greater than simply additive are indicated by an asterisk.

                                      TABLE 1                                     __________________________________________________________________________    Synergistic Effect of Compound I/Cymoxanil Combination on Potato Late         Blight                                                                                       Percentage disease control                                                    Experimental.sup.(2)                                                                      Expected.sup.(3)                                   Compound                                                                             Rate g ai/ha.sup.(1)                                                                  Test 1                                                                            Test 2                                                                            Ave Test 1                                                                            Test 2                                                                            Ave                                        __________________________________________________________________________    cymoxanil                                                                            8       0   20  10  --  --  --                                         cymoxanil                                                                            35      0   25  12.5                                                                              --  --  --                                         cymoxanil                                                                            140     41  51  46  --  --  --                                         Compound I                                                                           8       69  77  73  --  --  --                                         Compound I                                                                           35      87  98  92.5                                                                              --  --  --                                         Compound I                                                                           140     90  98  94  --  --  --                                         cymoxanil + I                                                                        8 + 8   *77 *95 *86 69  82  76                                         cymoxanil + I                                                                         8 + 35 *98 98  *98 87  98  93                                         cymoxanil + I                                                                         8 + 140                                                                              *95 *99 *97 90  98  95                                         cymoxanil + I                                                                        35 + 8  *75 74  74.5                                                                              69  83  76                                         cymoxanil + I                                                                        35 + 35 *91 98  *94.5                                                                             87  99  93                                         cymoxanil + I                                                                         35 + 140                                                                             *98 *100                                                                              *99 90  99  95                                         cymoxanil + I                                                                        140 + 8 *95 86  *90.5                                                                             82  89  85                                         cymoxanil + I                                                                        140 + 35                                                                              *98 *100                                                                              *99 92  99  96                                         cymoxanil + I                                                                        140 + 140                                                                             *98 98  *98 94  99  97                                         __________________________________________________________________________     .sup.(1) grams of active ingredient per hectare.                              .sup.(2) actual control observed.                                             .sup.(3) expected control calculated from Colby equation.                

EXAMPLE 3 Synergistic Combination of5-methyl-5-(4-phenoxyphenyl)-3-phenylamino-2,4-oxazolidinedione(Compound I) and Cymoxanil

Test compositions are prepared as follows: A stock solution of CompoundI is prepared from 1825 mg of a 2% emulsifiable concentrate (EC)containing Compound I (36.5 mg of active ingredient) as described inExample 2. A 2% EC of Compound I is prepared by dissolving 25.51 g ofCompound I into a solvent mixture consisting of 37.5 g of Atlox® 3453,37.5 g of Atlox® 3404, 62.5 g of n-butanol, and 1112.5 g ofacetophenone. Atlox® 3453 and Atlox® 3494 are available from ICIAmericas, Inc., New Murphy Road and Concord Pike, Wilmington, Del.19807. A stock solution of cymoxanil is prepared from a 50% WPformulation of Curzate® in a manner similar to that described in Example2. The stock solutions are then diluted with distilled water asdescribed in Example 2 to effect application rates of 70g ai/ha, 140gai/ha, and 280 g ai/ha. These dilutions are then applied to the testplants by spraying following the procedures described in Example 2.

The composition prepared above is tested as follows. The test conditionsare identical as those described for Example 2 except that (i) the testrates for cymoxanil were 70 and 140 g ai/ha (ii) the test rates forCompound I were 140 and 280 g ai/ha and (iii) the plants are maintainedin a greenhouse for 2 days after spraying and are then inoculated. Themean percentage disease control is summarized in Table 2. Tests wherethe control level is greater than simply additive are indicated by anasterisk.

                  TABLE 2                                                         ______________________________________                                        Synergistic Effect of Compound I/Cymoxanil                                    Combination on Potato Late Blight                                                             Percentage disease control                                    Compound Rate g ai/ha.sup.(1)                                                                       Experimental.sup.(2)                                                                     Expected.sup.(3)                             ______________________________________                                        cymoxanil                                                                              70           14         --                                           cymoxanil                                                                              140          56         --                                           Compound I                                                                             140          62         --                                           Compound I                                                                             280          71         --                                           cymoxanil + I                                                                           70 + 140    *81        67                                           cymoxanil + I                                                                           70 + 280    *89        83                                           cymoxanil + I                                                                          140 + 140    *77        75                                           cymoxanil + I                                                                          140 + 280    *91        87                                           ______________________________________                                         .sup.(1) grams of active ingredient per hectare.                              .sup.(2) actual control observed.                                             .sup.(3) expected control calculated from Colby equation.                

EXAMPLE 4 Synergistic Combination of5-methyl-5-(4-phenoxyphenyl)-3-phenylamino-2,4-oxazolidinedione(Compound I) and Cymoxanil

A 2% EC of Compound I is prepared by the procedure described in Example3. Stock solutions and dilutions of Compound I and Cymoxanil areprepared by the procedures described in Example 3. These dilutions arethen applied to the test plants by spraying following the proceduresdescribed in Example 2.

Potatoes (Solanum tuberosum `Superior`) grown from tissue culture aretransplanted to 4-inch (10.16 cm) pots and maintained in the greenhouse.Five to six weeks after transplanting, uniform plants 6-8 inches(15.24-20.32 cm) tall are selected. The plants are sprayed withcymoxanil alone at rates of 70 and 140 g ai/ha, or with Compound I aloneat rates of 140 and 280 g ai/ha or with combinations of cymoxanil andCompound I in all rate combinations. After spraying, the plants aremaintained in a greenhouse for 6 days. Plants are then inoculated withan aerosol suspension of P. infestans zoospores (2×10⁴ zoospores/mL) indeionized water. The plants are then immediately placed in ahumidification chamber (>98% relative humidity) for 24 hours to provideenvironmental conditions necessary for infection afterwards. After thehumidification period, plants are sprayed a second time with the sametreatments applied earlier. After drying, plants are given a 24-hourtransition period in a lighted growth chamber and returned to thegreenhouse. Disease is evaluated 6 days after inoculation by recordingthe percentage of leaf surface with typical P. infestans lesions on thebasal four fully expanded true leaves. Each treatment is replicated 3times. The mean percentage disease control is summarized in Table 3.Tests where the control level is greater than simply additive areindicated by an asterisk.

                  TABLE 3                                                         ______________________________________                                        Synergistic Effect of Compound I/Cymoxanil                                    Combination on Potato Late Blight                                                             Percentage disease control                                    Compound Rate g ai/ha.sup.(1)                                                                       Experimental.sup.(2)                                                                     Expected.sup.(3)                             ______________________________________                                        cymoxanil                                                                              70           65         --                                           cymoxanil                                                                              140          91         --                                           Compound I                                                                             140          62         --                                           Compound I                                                                             280          80         --                                           cymoxanil + I                                                                           70 + 140    *92        86                                           cymoxanil + I                                                                           70 + 280    *99        93                                           cymoxanil + I                                                                          140 + 140    *99        96                                           cymoxanil + I                                                                          140 + 280    *100       98                                           ______________________________________                                         .sup.(1) grams of active ingredient per hectare.                              .sup.(2) actual control observed.                                             .sup.(3) expected control calculated from Colby equation.                

EXAMPLE 5 Synergistic Combination of5-methyl-5-(4-phenoxyphenyl)-3-phenylamino-2,4-oxazolidinedione(Compound I) and Cymoxanil

This test is performed using compositions of Compound I and cymoxanilwhich are prepared by dissolving each compound in acetone and thendiluting each solution with water containing a non-ionic surfactant togive a final stock solution consisting of the active ingredient in 1:1acetone:water containing 0.02% by volume of a non-ionic surfactant. Thedilutions are prepared in a manner similar to those described in Example2. These dilutions are then applied to the test plants by sprayingfollowing the procedures described in Example 2.

After spraying, the plants are returned to the greenhouse. On day 1after spraying, plants are moved into a humidification chamber (>98%relative humidity) for 8 hours at which time they are placed in alighted growth chamber (20° C.) for 16 hours. This cycle is repeated onday 2 after spraying. On day 3 after spraying, plants are returned tothe greenhouse and maintained for 3 days until inoculation.

Plants are then inoculated with an aerosol suspension of P. infestanszoospores (2×10⁴ zoospores/mL) in deionized water. The plants are thenimmediately placed in a humidification chamber (>98% relative humidity)for 24 hours to provide environmental conditions necessary for infectionafterwards and, following a 24 hour transition period in a lightedgrowth chamber, the plants are returned to the greenhouse. Disease isevaluated 6 days after inoculation by recording the percentage of leafsurface with typical P. infestans lesions on the basal four fullyexpanded true leaves. Each treatment is replicated 5 times for eachtest. The test is repeated twice and the mean percentage disease controlsummarized in Table 4 is the average of both tests. Treatments where thecontrol level is greater than simply additive are indicated by anasterisk.

                  TABLE 4                                                         ______________________________________                                        Synergistic Effect of Compound I/Cymoxanil                                    Combination on Potato Late Blight                                                             Percentage disease control                                    Compound Rate g ai/ha.sup.(1)                                                                       Experimental.sup.(2)                                                                     Expected.sup.(3)                             ______________________________________                                        cymoxanil                                                                              100          38         --                                           cymoxanil                                                                              250          47         --                                           cymoxanil                                                                              625          41         --                                           Compound I                                                                             15           59         --                                           Compound I                                                                             30           66         --                                           Compound I                                                                             60           91         --                                           Compound I                                                                             120          94         --                                           cymoxanil + I                                                                          100 + 15     48         75                                           cymoxanil + I                                                                          100 + 30     *80        79                                           cymoxanil + I                                                                          100 + 60     *98        94                                           cymoxanil + I                                                                           100 + 120   96         96                                           cymoxanil + I                                                                          250 + 15     45         78                                           cymoxanil + I                                                                          250 + 30     *84        82                                           cymoxanil + I                                                                          250 + 60     *97        95                                           cymoxanil + I                                                                           250 + 120   95         97                                           cymoxanil + I                                                                          625 + 15     68         76                                           cymoxanil + I                                                                          625 + 30     *96        80                                           cymoxanil + I                                                                          625 + 60     *100       95                                           cymoxanil + I                                                                           625 + 120   99         96                                           ______________________________________                                         .sup.(1) grams of active ingredient per hectare.                              .sup.(2) actual control observed, average of two separate tests.              .sup.(3) expected control calculated from Colby equation.                

EXAMPLE 6 Synergistic Combination of5-methyl-5-(4-phenoxyphenyl)-3-phenylamino-2,4-oxazolidinedione(Compound I) and Cymoxanil

This test is performed using compositions of Compound I and cymoxanilwhich are prepared by dissolving each compound in acetone and thendiluting each solution with water containing a non-ionic surfactant togive a final stock solution consisting of the active ingredient in 1:1acetone:water containing 0.02% by volume of a non-ionic surfactant. Thedilutions are prepared in a manner similar to those described in Example2. These dilutions are then applied to the test plants by sprayingfollowing the procedures described in Example 2.

Seedling grape plants (Vitis vinifera `Chardonnay`) are grown in 2-inch(5-cm) square plastic pots and maintained in a growth chamber at 27° C.and 16-hour photoperiod. When plants are approximately 24 inch (5-10 cm)tall, uniform plants are selected for testing. Plants are sprayed withcymoxanil alone at 7.8, 31.3, 125 and 500 g ai/ha, or with Compound Ialone at rates of 0.31, 1.25, 5 and 20 g ai/ha or with combinations ofcymoxanil and Compound I in all rate combinations. After spraying,plants are returned to the growth chamber. On day 1 after spraying,plants are moved into a humidification chamber (>98% relative humidity)for 16 hours at which time they are returned to the growth chamber for 8hours. This cycle is repeated on days 2,4 and 5 after spraying. On day 6after spraying, plants are returned to the growth chamber and maintainedfor 1 day until inoculation. Plants then are inoculated with an aerosolsuspension of Plasmopara viticola zoospores (2.5×10⁴ zoospores/mL) indeionized water. Inoculated plants immediately are placed in ahumidification chamber for 24 hours to provide environmental conditionsnecessary for infection. Plants then are returned to the growth chamberfor 6 days, at which time they are returned to the humidificationchamber for 24 hours to induce sporulation. Disease severity isevaluated by recording the percentage of leaf surface with typical P.viticola lesions and sporulation on the basal three fully expanded trueleaves of each plant. Each treatment is replicated 5 times for eachtest. The mean percentage disease control ((% disease in check)-(%disease in treated))/(% disease in check)×100! is summarized in Table 5.Tests where the control level is greater than simply additive areindicated by an asterisk.

                  TABLE 5                                                         ______________________________________                                        Synergistic Effect of Compound I/Cymoxanil                                    Combination on Grape Downy Mildew                                             Compound Rate g ai/ha.sup.(1)                                                                       Experimental.sup.(2)                                                                     Expected.sup.(3)                             ______________________________________                                        cymoxanil                                                                              7.8          2          --                                           cymoxanil                                                                              31.3         3          --                                           cymoxanil                                                                              125          28         --                                           cymoxanil                                                                              500          99         --                                           Compound I                                                                             0.31         20         --                                           Compound I                                                                             1.25         18         --                                           Compound I                                                                             5            71         --                                           Compound I                                                                             20           99         --                                           cymoxanil + I                                                                           7.8 + 0.31  4          22                                           cymoxanil + I                                                                           7.8 + 1.25  15         20                                           cymoxanil + I                                                                          7.8 + 5      *77        72                                           cymoxanil + I                                                                          7.8 + 20     99         99                                           cymoxanil + I                                                                          31.3 + 0.31  2          22                                           cymoxanil + I                                                                          31.3 + 1.25  16         20                                           cymoxanil + I                                                                          31.3 + 5     64         72                                           cymoxanil + I                                                                          31.3 + 20    98         99                                           cymoxanil + I                                                                           125 + 0.31  34         47                                           cymoxanil + I                                                                           125 + 1.25  *87        41                                           cymoxanil + I                                                                          125 + 5      *96        79                                           cymoxanil + I                                                                          125 + 20     99         99                                           cymoxanil + I                                                                           500 + 0.31  *100       99                                           cymoxanil + I                                                                           500 + 1.25  100        100                                          cymoxanil + I                                                                          500 + 5      100        100                                          cymoxanil + I                                                                          500 + 20     99         100                                          ______________________________________                                         .sup.(1) grams of active ingredient per hectare.                              .sup.(2) actual control observed, average of two separate tests.              .sup.(3) expected control calculated from Colby equation.                

EXAMPLE 7 Synergistic Combination of5-methyl-5-(4-phenoxyphenyl)-3-phenylamino-2,4-oxazolidinedione(Compound I) and Cymoxanil

Test compositions are prepared as follows: A portion of a 200 g/Lsuspension concentrate (20% SC) containing Compound I is diluted with2000 parts of distilled water to form a 100 ppm test solution ofCompound I. A 200 g/L suspension concentrate of Compound I is preparedfrom Compound I (204.08 g, 98%), Supermontaline SLT 70 (4.00 g),monopropylene glycol (50.00 g), Rhodorsil 454 (2.00 g), acetic acid(33.67 g, 80%), sodium acetate trihydrate (62.00 g), Bronopol (1.00 g),Attagel 50 (10.00 g), water (509.25 g), Emcol® 4100 (50.00 g), CulminalMHPC50 (1.00 g) and Atplus 469 (200.00 g) by preparation of a slurry bycombining the Compound I, the Supermontaline SLT 70, the monopropyleneglycol, half of the Rhodorsil 454, the acetic acid, the sodium acetatetrihydrate, the Bronopol, the Attagel 50, the main part of the water,the Emcol® 4100, the Culminal MHPC50 and the Atplus 469 (as a 5% aqueoussolution prepared with part of the water) under mixing; the slurry isthen agitated for one hour before being wet milled with a Dynomill; themilling chamber is 85-87% filled (by volume) with glass beads having adiameter range of 0.5-0.75 mm, the peripheral speed of the mill discs isadjusted to 14 m/s, the slurry is fed to the mill at a rate of 40 mL/minand two passes are necessary to get the desired particle size (averageparticle size below 1 elm); the remaining half of the Rhodorsil 454, theAtplus 469 and the remaining part of the water are successively addedunder agitation and the suspension is agitated for a half-hour.Cymoxanil is used as the commercially available 50% wettable powder (WP)formulation of Curzate®. A portion of the 50% WP of cymoxanil is dilutedwith 5000 parts of distilled water to form a 100 ppm test solution ofcymoxanil. A portion of a 100 g/L+100 g/L suspension concentrate(10%+10% SC) containing Compound I and cymoxanil is diluted with 1000parts and 2000 parts of distilled water to form 100+100 ppm and 50+50ppm test solutions of Compound I and cymoxanil, respectively. A 100 g/L+100 g/L suspension concentrate (10%+10% SC) of Compound I and cymoxanilis prepared from Compound I (102.04 g, 98%), cymoxanil (104.17 g, 96%),Supermontaline SLT 70 (2.00 g), monopropylene glycol (50.00 g),Rhodorsil 454 (2.00 g), acetic acid (26.73 g, 80%), sodium acetatetrihydrate (16.37 g), Bronopol (1.00 g), Attagel 50 (2.50 g), Reax 85(25.00 g), Morwet D425 (12.5 g), Aerosil 200 (2.50 g), Kelzan® S (0.10g), Brij 78 (200.00 g) and water (552.66 g) by preparation of a slurryby adding the main part of Compound I and heating to 60° C.; adding theBrij 78, the acetic acid and the sodium acetate trihydrate under mixingand waiting until the Brij 78 is completely dissolved; theSupermontaline SLT 70, the monopropylene glycol, half of the Rhodorsil454, the Bronopol, the Attagel 50, the Reax 85, the Morwet D425, Aerosil200, the remaining part of Compound I and the cymoxanil are added undermixing while the slurry is cooling to room temperature; the slurry isthen agitated for one hour before being wet milled with a Dynomill; themilling chamber is 85-87% filled (by volume) with glass beads having adiameter range of 0.5-0.75 mm, the peripheral speed of the mill discs isadjusted to 14 m/s, the slurry is fed to the mill at a rate of 40 mL/minand two passes are necessary to get the desired particle size (averageparticle size below 1 μm); the remaining half of the Rhodorsil 454 andthe Kelzan® S (as a 2% aqueous solution prepared with the remaining partof the water) are added to the milled slurry under agitation and thesuspension is agitated for a half-hour.

Tomatoes (var. Houryu) are grown in a greenhouse. The test has fivereplicates (each replicate of one plant per pot). Test solutions areapplied at 100 mL per pot (equivalent to 3000 L/ha; 100 ppm and 50 ppmtest solutions provide application rates equivalent to 300 g/ha and 150g/ha, respectively). Plants are sprayed the following day with asuspension of zoospores of Phytophthora infestans, the cause of tomatolate blight. This inoculation is done using a small sprayer to depositinoculum to eight leaves on each plant. After inoculation, pots are keptin a lighted incubator at 23° C. and 100% relative humidity for twodays. All eight inoculated leaves per plant are evaluated the followingday by recording the percentage of leaf surface with P. infestanslesions. The mean percentage disease control is summarized in Table 6.

Treatments where the control level is greater than simply additive areindicated by an asterisk.

                  TABLE 6                                                         ______________________________________                                        Synergistic Effect of Compound I/Cymoxanil                                    Combination on Tomato Late Blight                                                             Percentage disease control                                    Compound  Rate g ai/ha.sup.(1)                                                                      Experimental.sup.(2)                                                                     Expected.sup.(3)                             ______________________________________                                        cymoxanil 300          93        --                                           (50% WP)                                                                      Compound I                                                                              300          74        --                                           (20% SC)                                                                      cymoxanil + I                                                                           300 + 300   *100       98                                           (10% + 10% SC)                                                                cymoxanil + I                                                                           150 + 150   *100.sup.(4)                                                                             --                                           (10% + 10% SC)                                                                ______________________________________                                         .sup.(1) grams of active ingredient per hectare.                              .sup.(2) actual control observed, average of two separate tests.              .sup.(3) expected control calculated from Colby equation.                     .sup.(4) 300 total g ai/ha of the 1:1 composition provided greater contro     than 300 g ai/ha of either compound alone.                               

What is claimed is:
 1. A fungicidal composition comprising: asynergistic fungicidally effective amount of a mixture of (a) at leastone compound selected from5-methyl-5-(4-phenoxyphenyl)-3-phenylamino-2,4-oxazolidinone andagriculturally suitable salts thereof, and (b) at least one compoundselected from cymoxanil and agriculturally suitable salts thereof,wherein the weight ratio of component (a) to component (b) is from 17:1to 1:100.
 2. A fungicidal composition of claim 1 further comprising atleast one of a surfactant, a solid diluent or a liquid diluent.
 3. Afungicidal composition of claim 2 wherein the weight ratio of component(a) to component (b) is from 8:1 to 1:25.
 4. A fungicidal composition ofclaim 3 wherein the weight ratio of component (a) to component (b) isfrom 4:1 to 1:10.
 5. A fungicidal composition of claim 4 wherein theweight ratio of component (a) to component (b) is from 3:2 to 1:3.
 6. Amethod for controlling plant diseases caused by fungal plant pathogenscomprising: applying to the plant or portion thereof to be protected, orto the plant seed or seedling to be protected, an effective amount of afungicidal composition comprising (a) the compound of Formula I ##STR6##or an agriculturally suitable salt thereof, (b) cymoxanil, or anagriculturally suitable salt thereof, and (c) at least one of asurfactant, a solid diluent or a liquid diluent; the weight ratio of thecompound of (a) to the compound of (b) applied being from about 17:1 to1:100, and the compound of (a) and the compound of (b) being applied inamounts effective to provide synergistic control of the fungal disease.7. The method of claim 6 wherein the fungal plant pathogen isPhytophthora infestans.
 8. The method of claim 6 wherein the fungalplant pathogen is Plasmopara viticola.
 9. A method for controlling plantdiseases caused by fungal plant pathogens comprising: applyingsequentially in any order to the plant or portion thereof to beprotected, or to the plant seed or seedling to be protected, (i) aneffective amount of a first composition comprising (a) the compound ofFormula I ##STR7## or an agriculturally suitable salt thereof, and (c1)at least one of a surfactant, a solid diluent or a liquid diluent; and(ii) an effective amount of a second composition comprising (b)cymoxanil, or an agriculturally suitable salt thereof, and (c2) at leastone of a surfactant, a solid diluent or a liquid diluent; the weightratio of the compound of (a) to the compound of (b) applied being fromabout 17:1 to 1:100, and the compound of (a) and the compound of (b)being applied in amounts effective to provide synergistic control of thefungal disease.
 10. A method for controlling plant diseases caused byfungal plant pathogens comprising: applying to the plant or portionthereof to be protected, or to the plant seed or seedling to beprotected, an effective amount of a physical mixture of (i) a firstcomposition comprising (a) the compound of Formula I ##STR8## or anagriculturally suitable salt thereof, and (c1) at least one of asurfactant, a solid diluent or a liquid diluent; and (ii) a secondcomposition comprising (b) cymoxanil or an agriculturally suitable saltthereof and (c2) at least one of a surfactant, a solid diluent or aliquid diluent; the weight ratio of the compound of (a) to the compoundof (b) applied being from about 17:1 to 1:100, and the compound of (a)and the compound of (b) being applied in amounts effective to providesynergistic control of the fungal disease.
 11. The method of claim 9wherein the fungal plant pathogen is Phytophthora infestans.
 12. Themethod of claim 9 wherein the fungal plant pathogen is Plasmoparaviticola.
 13. The method of claim 10 wherein the fungal plant pathogenis Phytophthora infestans.
 14. The method of claim 10 wherein the fungalplant pathogen is Plasmopara viticola.